Comparison between loureirin A and cochinchinenin C on the interaction with human serum albumin

• The interaction between LA (or CC) and human serum albumin has been investigated.
• LA and CC quench the HSA fluorescence through a combined quenching.
• The binding affinity of CC to HSA was more than that of LA at low concentrations.
• LA (or CC) bind to HSA is mainly through hydrogen bonds and van der Waals forces.
• The binding study was also modeled by molecular docking.

The interactions of loureirin A (LA) and cochinchinenin C (CC) with human serum albumin (HSA) under simulated physiological conditions (pH = 7.4) have been studied with fluorescence, UV–vis absorption spectroscopic method and molecular docking technique. The results indicated that there was a synergistic interaction between LA and CC, and the fluorescence quenching of HSA by LA (or CC) was a combined quenching procedure (dynamic and static quenching). At low compound concentrations, the quenching constants KSV of CC was larger than that of LA, which meant the CC efficacy may be better than that of LA. The negative △H and △S values suggested hydrogen bonds and van der Waals forces played the major role in the binding of LA (or CC) to HSA. The efficiency of energy transfer and distance between the compounds and HSA was calculated. Moreover, the results of synchronous and three-dimensional fluorescence demonstrated that the HSA microenvironment was changed in the presence of LA (or CC). Finally, the binding of LA (or CC) to HSA was modeled by molecular docking, which is in good accordance with the experimental studies.

The interaction of loureirin A with human serum albumin has been studied by fluorescence spectroscopic method and molecular docking technique. The quenching constants and mechanism on interactions were determined.Figure optionsDownload as PowerPoint slide